first handgun, i will suggest a semi auto pistol in 22lr to start with. to learn the basics of pistol shooting. you can buy a box of 500-550 rounds for usually less than $20 at most places. this will give you the cheapest way to practice. learn the basics with the 22, then step up in caliber when you get good shooting the 22. the first pistol i ever shot when i was much younger, was a 9 shot, 6" barreled revolver. the lack of recoil of the 22 will allow you to develop good shooting habits that you will need for shooting larger calibered pistols. you need to learn to walk, before you can run, and this applies to shooting pistols and rifles.

I have a .25 astra firecat pistol I've shot many times. I want to amp up the caliber because Im proficient with this pistol and I'm looking for a larger one typically for home defense and shooting at the range

9mm is the best option if you're learning and intending to frequently shoot a defensive pistol on a budget. I like CZ and Sig for metal framed guns, and feel most of the the polymer staples (Glock, XD/XDm, FN, SW M&P, etc) are on pretty equal footing. Simply getting a grip on as many possible will offer pretty solid insight into which fits you best.